Blackie attends a Christmas show in a prison and is amused by the performances of some of the more talented inmates, including Parks whose magic act is a cover for a prison break. (A similar technique was used for a crashout in Bogart's THE BIG SHOT.) Parks escapes, Blackie on his tail.
Parks is determined to track down and kill the double who is really responsible for the crime that imprisoned him. Blackie not only recaptures Parks but apprehends the doppelganger which leads to the release of the innocent man.